Poison ivy and poison oak dermatitis represent a major occupational, as well as recreational hazard. This is particularly so for forest workers. From 1976 to 1977, Oregon forest workers insured by the State Accident Insurance Fund had 27.7% of their injuries and illnesses attributable to dermatitis--most of which was from poison oak and poison ivy. It is our intention to try to develop an active protective cream which will prevent poison oak/ivy dermatitis. The allergenic principle of poison oak/ivy is known to be 3-pentadecylcatechol (3-PDC) and three related structures with increasing degrees of unsaturation of the 15-carbon side chain. Currently, it is believed that the catecholic portion undergoes oxidation to form the quinone. The quinone, being more reactive than the catechol, then reacts with the thiol and amino groups of proteins to form a 3-PDC:protein conjugate. The resulting conjugate is thought to represent the active allergen. This sequence of steps could be prevented in one of the following ways: 1) keeping the catechol in the reduced form with reducing agents, 2) providing an alternate substance for the quinone to conjugate with, 3) changing the permeability properties of the skin. Several chemical agents have these properties and, as such, may be able to prevent poison oak/ivy dermatitis. Evaluation of the efficacy of simple creams containing one or more of these agents may be accomplished simply and reliably using patch tests technique has been standardized by the North American Contact Dermatitis Group and is a commonly used procedure in dermatology. Testing would involve the application of protective agents to the subject's back followed by "challenge" with poison oak/ivy extract under occlusion. Different concentrations of protective agents and different vehicles will be tested with the aim of being able to determine the degree of protection provided by the various protective agents. The validity of the quinone hypothesis of allergenicity will also be evaluated. Conjugates of 3-PDC and an amino acid or protein will be synthesized in vitro, then evaluated using the closed patch test system to determine if the allergenicity of the 3-PDC portion has been destroyed.